Liquid hydrocarbon fuel from methane assisted by spontaneously generated voltage

ABSTRACT

A methane-containing gas such as natural gas is converted to a clean-burning hydrocarbon liquid fuel in a process wherein the gas is fed to a reaction vessel to contact a metallic catalyst grid that is formed from windings of a transition metal supported on an iron frame immersed in a liquid petroleum fraction, in such a manner that a voltage is generated in the grid between the windings and the frame. Product gas in the vapor phase is drawn from the head space above the liquid level and condensed to form the product fuel.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of co-pending application Ser. No.12/551,264, filed Aug. 31, 2009, the contents of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention resides in the field of petroleum-derived liquid fuelsand particularly in the conversion of methane to liquid hydrocarbons.

2. Description of the Prior Art

Alternative sources of automotive fuel are in ever increasing demand ascrude oil fluctuates in price and as governments and the public at largebecome increasingly concerned over the gaseous and particulate emissionsthat the processing of crude oil releases into the atmosphere. Naturalgas is an abundant resource in many parts of the world that do not havenative supplies of crude oil and in many cases, the cost of extractingnatural gas from its natural reservoirs is significantly lower than thatof extracting crude oil. For a variety of reasons, however, includingits special requirements for transport and storage, natural gas does notoffer the full range of uses that are offered by liquid fuels.

This invention provides a means of converting natural gas, andmethane-containing gases in general, to a liquid fuel. In addition, theinvention can result in the production of a liquid fuel of surprisinglyefficient energy output and versatility.

SUMMARY OF THE INVENTION

It has now been discovered that a fluctuating electric potential can begenerated in a reaction vessel by passing a methane-containing gasacross a catalytic metallic grid that is immersed in a liquid petroleumfraction, and that the potential thus generated contributes to achemical reaction between the methane and the liquid petroleum fractionto produce an unusually high-performing liquid fuel. The electricpotential is spontaneously generated, without being initiated orsupplemented by an externally imposed potential, and can be detectedbetween sites on the metallic grid. Notably, for a grid that consists ofwindings of a conductive metal or combination of conductive metals, suchas two or more transition metals and preferably also aluminum, over aniron frame, the electric potential can be measured between the windingsand the iron frame. The fluctuations of the potential are generallyirregular in both amplitude and frequency, but with a time-averagedvalue that significantly exceeds, by at least a factor of ten, the valueof any such potential that exists between the same sites on the immersedcatalyst grid in the absence of the gas flow through the grid.

The liquid fuel produced by the catalytic reaction between themethane-containing gas and the liquid petroleum fraction is recovered bycondensing the gaseous effluent collected from the reaction medium, andit has further been discovered that the product fuel is bothclean-burning and highly efficient. When used as an automotive fuel, thefuel produced by this invention produces a mileage that significantlyexceeds that of conventional fuels, including that of the liquidpetroleum fraction used as the reaction medium. Thus, for example, whenthe liquid petroleum fraction is diesel oil, the product fuel producesapproximately 30% or more miles per gallon, or other equivalent measureof fuel efficiency, than the starting diesel oil. Furthermore, the rateat which the product fuel is produced far exceeds any rate of depletionof the liquid reaction medium.

These and other objects, advantages, and features of the invention arebetter understood by the description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram embodying an example of animplementation of the invention.

FIG. 2 is a top view of a catalyst grid used in the reactor shown in theprocess flow diagram of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

The methane-containing gas used in the practice of the present inventionis preferably a gas in which methane constitutes the major component.Examples are naturally occurring gas as well as industrial gases, andspecific examples are coal bed methane, coal mine methane, abandonedmine methane, refinery gas, associated gas, digester gas, and naturalgas. Gases containing about 70% or more methane by volume are preferred,more preferably about 85% or more by volume, and most preferably about93% or more by volume. Natural gas containing about 95% methane byvolume is particularly preferred. Natural gas when used is preferablyused without supplementation with other gases, and particularly withoutsignificant amounts of hydrogen or carbon monoxide, and notably lessthan 1% by volume of each.

Petroleum fractions for use as the liquid reaction medium in thisinvention include fossil fuels, crude oil fractions, and many of thecomponents derived from these sources. Fossil fuels, as is known in theart, are carbonaceous liquids derived from petroleum, coal, and othernaturally occurring materials, and also include process fuels such asgas oils and products of fluid catalytic cracking units, hydrocrackingunits, thermal cracking units, and cokers. Included among thesecarbonaceous liquids are automotive fuels such as gasoline, diesel fuel,jet fuel, and rocket fuel, as well as petroleum residuum-based fuel oilsincluding bunker fuels and residual fuels. The term “diesel fuel”denotes fractions or products in the diesel range, such as straight-rundiesel fuel, feed-rack diesel fuel (diesel fuel that is commerciallyavailable to consumers at gasoline stations), light cycle oil, andblends of straight-run diesel and light cycle oil. The teem “crude oilfractions” includes any of the various refinery products produced fromcrude oil, either by atmospheric distillation or by vacuum distillation,as well as fractions that have been treated by hydrocracking, catalyticcracking, thermal cracking, or coking, and those that have beendesulfurized. Examples of crude oil fractions other than diesel oils arelight straight-run naphtha, heavy straight-run naphtha, lightsteam-cracked naphtha, light thermally cracked naphtha, lightcatalytically cracked naphtha, heavy thermally cracked naphtha, reformednaphtha, alkylated naphtha, kerosene, hydrotreated kerosene, gasolineand light straight-run gasoline, atmospheric gas oil, light vacuum gasoil, heavy vacuum gas oil, residuum, vacuum residuum, light cokergasoline, coker distillate, FCC (fluid catalytic cracker) cycle oil, andFCC slurry oil. Preferred liquids for the reaction medium are mineraloil, diesel oil, naphtha, kerosene, gas oil, and gasoline. Morepreferred are diesel oil, kerosene, and gasoline, and the most preferredare kerosene and diesel oil.

The transition metal catalyst can be a single transition metal or acombination of transition metals, either as metal salts, pure metals, ormetal alloys, and can also be used in combination with metals other thantransition metals. Preferred catalysts for use in this invention aremetals and metal alloys. Transition metals having atomic numbers rangingfrom 23 to 79 are preferred, and those with atomic numbers ranging from24 to 74 are more preferred. Cobalt, nickel, tungsten, particularly incombination, are the most preferred. An example of an additional metalthat can be included is aluminum.

The transition metal(s), together with other metals such as aluminumwhen included, are formed as windings supported on an iron frame. Thecatalyst is thus configured as a fixed bed secured to the interior ofthe reaction vessel. A variety of forms of iron can be used as the framematerial. Examples are pig iron, gray iron, and ductile iron. The metalwindings can be supported on the iron frame in the form of an open-meshnetwork, and the windings are preferably supported on the frame by beingwound around pegs affixed to the frame, where the pegs are formed of amaterial that has an electrical resistivity that is substantially higherthan the electrical resistivities of both the windings and of the frame.In preferred embodiments, the electrical resistivity of the pegs is atleast about 15×10⁻⁸ ohm meters at 100° C. Chromium and chromium alloysare examples of materials that meet this description.

The electric potential produced in the reactor can be detected betweenthe windings and the iron frame. The potential will vary with thedistance between the site on the windings and the site on the framebetween which the electrical contacts is measured, and in some cases,with the locations of the sites themselves. In general, the greater thedistance, the larger the potential. When the frame is circular in outerdiameter with reinforcing bars or rods within the perimeter and thewindings converge at the center of the frame, the electric potential ismost effectively measured between the windings at the center and theframe itself at a location that is at a radial distance from the center,for example a distance equal to approximately half the radius of theframe. With gas feed rates to the reactor of 50 standard cubic feet perhour (SCFH) or greater, the electric potential between these points willbe at least about 100 mV, preferably from about 100 mV to about 10V,most preferably with a time-averaged value of from about 300 mV to about3V, and mean fluctuation frequencies of from about 30 Hz to about 300Hz. With gas feed rates within the range of about 10,000 cubic feet perhour to about 100,000 cubic feet per hour, the time-averaged electricpotential between these points can be from about 100 mV to about 200 mV,the maximum values can be from about 1V to about 5V, and the frequencycan be from about 50 sec⁻¹ to about 1,000 sec⁻¹.

Contact between the methane-containing gas and the liquid petroleumfraction is achieved by conventional gas-liquid contacting methods. Aparticularly convenient means of contact as presently contemplated is bybubbling the gas through an otherwise static body of liquid in atank-form reaction vessel and drawing product vapor from a head spaceabove the liquid level in the reactor. The gas is preferably suppliedthrough one or more gas distributors immersed below the liquid level.Preferred distributors have a wheel-and-spokes configuration or a gridconfiguration, the wheel or grid being constructed from hollow pipeswith an array of apertures that release the gas in the form of smallbubbles into the liquid. The apertures, and if desired for ease ofconstruction, the pipes as well, can be covered with a mesh material tofurther reduce the sizes of the gas bubbles and to further disperse themas they proceed through the reaction medium. The mesh material can bemanufactured of any of the metals used as catalyst. Alternatively, aninert material such as a ceramic in the form of a conventional columnpacking material, can be used.

The reaction is performed under non-boiling conditions to maintain theliquid petroleum fraction that is used as the reaction medium in aliquid state and to prevent or at least minimize the vaporization of theliquid and its escape in unreacted form from the reaction vessel withthe product. An elevated temperature, i.e., a temperature above ambienttemperature, is used, preferably one that is about 80° C. or above, morepreferably one within the range of about 100° C. to about 250° C., mostpreferably within the range of about 100° C. to about 150° C. Theoperating pressure can vary as well, and can be either atmospheric,below atmospheric, or above atmospheric. The process is readily and mostconveniently performed at either atmospheric pressure or a pressuremoderately above atmospheric. Preferred operating pressures are thosewithin the range of about 1 atmosphere to about 2 atmospheres, mostpreferably within the range of about atmosphere to about 1.5atmospheres.

A process flow diagram representing one example of a plant design forimplementation of the present invention is presented in FIG. 1. Theplant includes a reaction vessel 11 and a product vessel 12, each ofwhich is a closed cylindrical tank. The reaction vessel 11 is chargedwith a petroleum fraction used as a liquid reaction medium 13 leaving agaseous head space 14 above the liquid. The liquid level is maintainedby a level control 15 which is actuated by a pair of float valves insidethe vessel. The level control 15 governs a motor valve 16 on a drainline 17 at the base of the vessel.

Natural gas or other methane-containing gas is fed to the reactionvessel 11 underneath the liquid level at an inlet gas pressure of fromabout 5 psig to about 20 psig, through a gas inlet line 18 which isdivided among two gas distributors 21, 22 inside the reactor vessel.Each distributor spans the full cross section of the vessel in either agrid configuration, a wheel-and-spokes configuration, or any otherconfiguration that will support an array of outlet ports distributedacross the cross section of the vessel. Two distributors are shown inthe Figure, but the number can vary. The optimal number of distributorsand outlet ports and the optimal configuration for any individualdistributor will be readily determinable by routine experimentation. Asingle distributor or three or more distributors may thus be optimal forreactor vessels of different capacities. A resistance heater 23 ispositioned in the reactor above the gas distributors, and a third gasdistributor 24 is positioned above the resistance heater. The third gasdistributor 24 receives return gas from the product receiving vessel 12as explained below.

Positioned above the three gas distributors 21, 22, 24 and theresistance heater 23 but still beneath the liquid level are a series ofcatalyst grids 25 arranged in a stack. Each grid is a circular ring orapertured plate with metallic catalyst wires strung across the ring andsupported by pegs affixed to the ring along the ring periphery. Thesizes of the wires and the total length of each wire will be selected toachieve the maximal surface area exposed to the reaction medium whileallowing gas to bubble through the grids. The selection of theseparameters for optimal results will be readily apparent to anyoneskilled in the use of metallic or other solid-phase catalysts in aliquid-phase or gas-phase reaction, or will be a matter of routineexperimentation. With wires that are 1 mm in diameter, for example, andwith individual wires of each of four metals, such as for examplecobalt, nickel, aluminum, and tungsten, two pounds of each metal wirecan be used per ring, or eight pounds total per ring. The number ofrings can vary, and will in most cases be limited only by the size ofthe reactor, the gas flow rate into the reactor, the desirability ofmaintaining little or minimal pressure drop across the rings, andeconomic factors such as the cost of materials. In a preferredembodiment, seven rings are used, each wound with the same number andweight of wires. The reaction can also be enhanced by placing screens ofwire mesh between adjacent plates to assure that the gas bubblescontacting the catalyst wires are of a small size. Screens that are40-mesh (U.S. Sieve Series) of either stainless steel or aluminum willserve this purpose.

Product gas is drawn from the head space 14 of the reaction vessel 11and passed through a supplementary catalyst bed of the same catalystmaterial as the catalyst grids 25 of the reaction vessel. In the diagramshown, two such supplementary catalyst beds 31, 32 of identicalconstruction and catalyst composition are arranged in parallel. Thesupplementary catalyst beds can be in the form of metallic wire screens,grids, or perforated plates similar to those of the catalyst grids 25 inthe reactor vessel 11. The supplementary catalyst promotes the samereaction that occurs in the reaction vessel 11 for any unreactedmaterials that have been carried over with the product gas drawn fromthe reaction vessel. Product gas emerging from the supplementarycatalyst beds is passed through a condenser 33, and the resultingcondensate 34 is directed to the product vessel 12 where it isintroduced under the liquid level in the product vessel.

The liquid level in the product vessel 12 is controlled by a levelcontrol 41 that is actuated by a pair of float valves inside the vesseland that governs a motor valve 42 on a liquid product outlet line 43 atthe base of the vessel. Above the liquid level is a packed bed 44 ofconventional tower packings. Examples are Raschig rings, Pall rings, andIntalox saddles; other examples will be readily apparent to thosefamiliar with distillation towers and column packings. The packingmaterial is inert to the reactants and products of the system, or atleast substantially so, and serves to entrap liquid droplets that may bepresent in the gas phase and return the entrapped liquid back to thebulk liquid in the lower portion of the vessel. Unreacted gas 45 iswithdrawn from the head space 46 above the packed bed by a gas pump 47.The pump outlet is passed through a check valve 48 and then directed tothe reaction vessel 11 where it enters through the gas distributor 24positioned between the resistance heater 23 and the catalyst grids 25.

FIG. 2 is a top view of one of the catalyst grids 25, showing the frame51 and only a portion of the windings 52 (in the actual construction,the windings will continue to cover the full circumference of theframe). Also shown are some of the pegs 53 around which the windings arewound. The electric potential discussed above can be measured betweenthe collected windings at the center 54 of the grid and a site 55 on theframe at a distance approximately half the length of the radius from thecenter.

Alternatives to the units described above and shown in the Figure willbe readily apparent to the skilled chemical engineer. Alternatives tothe resistance heater, for example, are heating jackets, heating coilsusing steam or other heat-transfer fluids, and radiation heaters.Heating of the reaction vessel can also be achieved, either in part orin whole, by recirculation of heat transfer fluid between the coolantside of the condenser and the reaction vessel. The gas distributors forthe inlet feed and the recycle gas can be any of a variety of typesknown in the art. Examples are perforated plates, cap-type distributors,and pipe distributors. The liquid level controls can likewise be any ofa variety of mechanisms known in the art. Examples are float-actuateddevices, devices measuring hydrostatic head, electrically actuateddevices such as those differentiating liquid from gas by electricalconductivity or dielectric constant, thermally actuated devices such asthose differentiating by thermal conductivity, and sonic devices basedon sonic propagation characteristics. The condenser can be replaced byany other known type of condenser. Examples of condensers in general areshell-and-tube condensers and plate-and-frame condensers, and among theshell-and-tube condensers are horizontal tube condensers and verticaltube condensers. Either co-current or counter-current condensers can beused, and the condensers can be air-cooled, water-cooled, or cooled byorganic coolant media such as automotive anti-freeze (for example, 50%pre-diluted ethylene glycol) and other glycol-based coolants.

Example 1

This example illustrates the present invention as applied to natural gasas the methane-containing gas and diesel oil as the liquid petroleumfraction. The equipment used was as shown in FIG. 1, in which thereaction vessel was a tank with a volumetric capacity of 1,000 gallons(3,785 liters) and a diameter of 6.5 feet (2 meters). The tank wasinitially charged with 600 gallons (2,270 liters) of diesel fuelmaintained at a temperature of 290° F. (143° C.) and a pressure of 6psig (143 kPa), and natural gas was bubbled through the reactor at arate of 20,000 SCFH. The catalyst grids consisted of nickel wire,tungsten wire, cobalt wire (an alloy containing approximately 50%cobalt, 10% nickel, 20% chromium, 15% tungsten, 1.5% manganese, and 2.5%iron), and aluminum wire over a gray iron frame. Once fully started, thereactor produced liquid product at a rate of 200 gallons per hour (760liters per hour), and two gallons of product for every gallon ofreaction medium depleted. All gallons listed herein are U.S. gallons.

The product was analyzed by standard ASTM protocols and the results arelisted in Table I.

TABLE I Product Test Results Protocol Result Flash Point ASTM D 93 64°C. Sediment and Water ASTM D2709 0.000 vol % Observed barometric 759mmHg pressure Percent Recovered: Result Distillation corrected to ASTM D86 Initial b.p. 179.9° C. 760 mmHg (1 atm)  5 193.8° C. 10 199.5° C. 15203.8° C. 20 208.0° C. 30 216.2° C. 40 223.4° C. 50 230.5° C. 60 238.0°C. 70 246.7° C. 80 257.3° C. 85 264.3° C. 90 272.9° C. 95 287.8° C. End296.1° C. Recovery 97.0% Viscosity @ 40° C. ASTM D 445a-1.8 1.83 mm²/sAsh ASTM D 482 <0.001 weight % Sulfur by ASTM D 3120 5 mg/kgMicrocoulometry Total Sulfur by UV ASTM 5453-1.0 2.4 mg/kg FluorescenceCopper Corrosion, ASTM D 130 1a 3 hours at 50° C. Cetane No. ASTM D61342.8 API Gravity at 60° F. ASTM D287 38.2 Deg. API Aromatics 18.1 volume% Olefins 1.6 volume % Saturates 80.3 volume % Cloud Point ASTM D2500−44° C. Ramsbottom Carbon ASTM D 524 0.06 weight % Residue, 10% BottomsLubricity by HFRR at 2809 μm 60° C. Total Nitrogen ASTM D 4629 7.7 mg/kgTotal Aromatics ASTM D 5186 19.2 weight % Mono-Aromatics ASTM D 518618.3 weight % Polynuclear Aromatic ASTM D 5186 0.9 weight % Hydrocarbons

Electrical measurements were taken between the windings at the center ofthe frame and the frame at a point midway between the center and theouter edge. At steady state, the measurements at one point in time werethose shown in Table II:

TABLE II Voltage Generated Voltage Period Frequency Rise Time Fall TimeMean 1.1160 V 41.7 msec 75.1 Hz 4.8 msec 4.6 msec Minimum 110 mV 16.4μsec 2.1 Hz −20.6 msec −221.4 μsec Maximum 4.243 V 482.7 msec 61.0 kHz461.1 msec 463.6 msec

The product was used as fuel in an F-150 Ford pick-up truck for citydriving in Reno, Nev., USA, to achieve a mileage of 14 miles/gal. Thesame pick-up truck normally obtains 10 miles/gal on gasoline. Theproduct was also used as fuel in Mercedes Benz 320S automobile in citydriving in Reno, Nev., USA, to achieve mileage of 30 miles/gal. Withcommercial diesel fuel, the same vehicle obtained 18 miles/gal. Theproduct was also used on a Hummer 1 automobile in city driving in Reno,Nev., USA, to achieve mileage of 12 miles/gal. With commercial dieselfuel, the same vehicle obtained 7 miles/gal.

Example 2

This example provides the results of emissions tests on two test fuelsmanufactured in accordance with the present invention and compares theseresults with results obtained on commercially available No. 2 Ultra LowSulfur Diesel (ULSD) fuel, all tests conducted in heavy-duty on-roaddiesel engines using the EPA Transient Cycle Heavy-Duty Test Protocol.The two test fuels were manufactured under the same conditions and inthe same equipment as that of Example 1, with kerosene as the liquidpetroleum faction in the first test fuel and No. 2 ULSD as the liquidpetroleum faction in the second test fuel, and natural gas (95% methane)as the methane-containing gas for both.

The heavy duty test engine used in the tests was a 1990 model yearCaterpillar diesel engine, Model No. 3406B. The test protocol is onethat is currently used for emission testing of heavy-duty on-roadengines in the United States, pursuant to 40 CFR §86.1333. The testbegins with a cold start after parking overnight, followed by idling,acceleration, and deceleration phases and subjects the engine to a widevariety of speeds and loads sequenced in a computer-controlled automaticengine dynamometer to simulate the running of the vehicle. There are fewstabilized running conditions, and the average load factor is about 20%to 25% of the maximum horsepower available at a given speed. The testcycle is twenty minutes in duration and two such cycles are performed,the first from a cold start and the second from a hot start twentyminutes after the end of the first cycle. The equivalent average speedis about 30 km/h and the equivalent distance traveled for each cycle is10.3 km. Emissions that were continuously measured and recorded everysecond included total hydrocarbons (THC), methane (CH₄), non-methanehydrocarbons (NMHC=THC−CH₄), carbon monoxide (CO), carbon dioxide (CO₂),oxides of nitrogen (NO_(x)), and nitrous oxide (NO₂). Fuel consumptionwas measured gravimetrically and reported in grams per brake horsepowerper hour (g/bhp-hr). Particulate matter (PM) was captured over theentire test cycle on a single filter medium and weighed. Anon-dispersive infrared detector was used for measuring CO and CO₂, aflame ionization detector was used for measuring THC and CH₄, a heatedchemiluminescent detector was used for measuring NO_(x) and NO, and PMwas measured by a primary tunnel dilution followed by secondary tunneldilution in a Model SPC-472 Smart Sampler of AVL Powertrain Engineering,Inc. The raw data were corrected by the computer for temperature,barometric pressure, and humidity, as well as for any hydrocarbons andcarbon monoxide present in the dilution air, and expressed as grams perbrake horsepower per hour.

The results are shown in Tables III and IV, where the “Baseline” valuesrepresent the results obtained with the commercially obtained No. 2 ULSDdiesel fuel.

TABLE III Emission Test Results - Raw Data bhp/hr HP HP grams g/bhp-hrDemand Actual THC NMHC CO NO_(x) CO₂ Fuel PM Baseline 24.37 23.01 4.203.94 64.5 233.4 15172.6 4371.5 0.224 Test Fuel 24.38 22.67 5.85 5.6164.7 208.0 14902.0 4364.0 0.243 No. 1 Deviation −1.5% 39.3% 42.4% 0.3%−10.9% −1.8% −0.2% 8.5% from Baseline Test Fuel 24.37 22.83 4.87 4.2266.2 215.5 14932.5 4388.0 0.214 No. 2 Deviation −0.8% 16.0% 7.1% 2.6%−7.7% −1.6% 0.4% −4.5% from Baseline

TABLE IV Emission Test Results - Corrected bhp/hr HP HP g/bhp-hr DemandActual THC NMHC CO NO_(x) CO₂ Fuel PM Baseline 24.37 23.01 0.18 0.172.81 10.15 659.46 0.4189 0.224 Test Fuel 24.38 22.67 0.26 0.25 2.86 9.18657.41 0.4244 0.243 No. 1 Deviation −1.5% 44.4% 47.1% 1.8% −9.6% −0.3%1.3% 8.5% from Baseline Test Fuel 24.37 22.83 0.20 0.18 2.90 9.44 654.130.4238 0.214 No. 2 Deviation −0.8% 11.1% 5.9% 3.2% −7.0% −0.8% 1.2%−4.5% from Baseline

In the claims appended hereto, the terms “a” and “an” are intended tomean “one or more.” The term “comprise” and variations thereof such as“comprises” and “comprising,” when preceding the recitation of a step oran element, are intended to mean that the addition of further steps orelements is optional and not excluded. All patents, patent applications,and other published reference materials cited in this specification arehereby incorporated herein by reference in their entirety. Anydiscrepancy between any reference material cited herein and an explicitteaching of this specification is intended to be resolved in favor ofthe teaching in this specification. This includes any discrepancybetween an art-understood definition of a word or phrase and adefinition explicitly provided in this specification of the same word orphrase.

What is claimed is:
 1. A liquid fuel prepared by a process comprising:(a) passing a gas containing at least about 70% methane by volumethrough a metallic catalyst grid immersed in a liquid petroleum fractionin a reaction vessel, with said liquid petroleum fraction at atemperature of about 80° C. or above but below the boiling temperatureof said liquid petroleum fraction, said metallic catalyst comprisingwindings of a transition metal supported on an iron frame, to produce afluctuating electric potential between said windings and said frame; (b)collecting a gaseous effluent from said reaction vessel; and (c)condensing said gaseous effluent to said liquid fuel.
 2. The liquid fuelof claim 1 wherein said gas is natural gas and said liquid petroleumfraction is diesel oil.
 3. The liquid fuel of claim 1 wherein saidwindings are made of a plurality of members selected from the groupconsisting of cobalt, nickel and tungsten.
 4. The liquid fuel of claim 1wherein said windings are comprised of cobalt, nickel and tungsten, andsaid catalyst further comprises windings of aluminum metal.
 5. Theliquid fuel of claim 1 wherein said fluctuating electric potential hasan time-averaged voltage of at least about 100 mV, a maximum voltage ofat least about 1,000 mV, and a frequency of at least about 50 sec⁻¹. 6.The liquid fuel of claim 1 wherein said gas is natural gas, said liquidpetroleum fraction is diesel oil, said catalyst is comprised of windingsof cobalt, nickel, tungsten, and aluminum, and said fluctuating electricpotential has an time-averaged voltage of from about 300 mV to about 3V,and a frequency of from about 30 Hz to about 300 Hz.